MicroLEDs industry is growing rapidly for a reason: they offer unmatched brightness, power savings, and fast response times. Their potential is remarkable beyond displays—they have even found use in flexible electronic skin for implanted microsensors.

In the global context, the microLED market size is expected to expand at a CAGR of 40.78% between 2024 and 2032. 

China, Taiwan, and Korea are the major stakeholders in the MicroLED market, hosting major companies such as Samsung, Konka, LG, TCL, and many others in microLED manufacturing.

Yole Développement’s analysis highlights a boom in microLED innovation, with over 5,500 patents filed by more than 350 organizations. Significantly, 40% of these patents were filed in 2019. 

MicroLED patent analytics highlights technological shifts, like transfer technologies and monolithic integration, and aids in navigating intellectual property, which is crucial for maintaining competitiveness in this rapidly evolving sector.

To help you have a birds-eye view of the latest developments, this article features the essential patents related to microLED innovation, including microLED patent analysis and notable innovations.  

MicroLED Patent Analysis: Latest Research and Key Innovations 

The future of MicroLED is being shaped by a series of notable innovations, many of which are protected by patents. Some pivotal areas of microLED patents and current research include the following: 

1. Mass Transfer

Traditional mechanical transfer equipment often fails to meet the requirements for transferring microLED chips in millions of mass production. 

Creating a 4K ultra-high definition (UHD) color TV requires a staggering 25 million microLED chip transfers. However, traditional transfer equipment and technology make this process incredibly slow, taking over two months.

In June 2023, LG Display acquired 14 microLED-related patents from Taiwan-based Ultra Display Technology in transfer technology. The mass transfer technology includes:

• PDMS Stamp Transfer: Polydimethylsiloxane (PDMS) stamp is non-toxic, stable, highly viscoelastic, transparent, and can be optically aligned.  It can transfer 82,863 chips of 75 μm × 90 μm with 99.99% yield in a single printing operation and can transfer chips of 3 μm in size.
  
• Laser-induced Forward Transfer: This technique can transfer about 1000 chips in one laser shot. However, it may cause depressions and cracks on the surface of the chip.
  
• Self-Assembly Transfer: Fluid-based assembly is a cost-effective technology and can be used to transfer large-pitch microLED. This technology can easily manage the microstructure on a large-area substrate with high yield.

2. Monolithic Integration

Recent research suggests that microLED arrays could produce R, G, B, and intermediate colors from one device, demonstrating the potential for monolithic integration, as predicted by Moore’s Law.

Some researchers have also used InGaN/GaN LED chips and vertical metal oxide semiconductor field effect transistors (VMOSFET) or AlGaN/GaN heterojunction field effect transistors (HFET) to achieve monolithic integration.

• Hwangbo et al. directly synthesized MoS2 thin films on GaN-based epitaxial wafers to form thin film transistor arrays. Subsequently, the MoS2 thin film transistor and the microLED device are monolithically integrated to make the AM microLED display. Incidentally, the MoS2 transistor is suitable for the reliable production of large-area microLED displays.
• The University of Sheffield reported a monolithically integrated microLED/high electron mobility transistors (HEMTs) display.
• Toyohashi University of Technology Tsuchiyama et al. used Si n-MOSFET and microLED chips for monolithic integration. 

3. MicroLED Detection and Repair Technology Developments

Mass transfer technology has made significant progress, but there are still some difficulties in the large-scale manufacturing of microLED displays. 

For instance, when microLED chips are used for display, the number of chips will reach millions or even tens of millions. Even if the yield is very high, bad spots will exist. 

Detection technologies mainly include photoluminescence (PL) detection and electroluminescence (EL) detection. 

• However, due to some shortcomings of PL and EL methods, methods of combining photoluminescence with other detection technologies are proposed. 

• Increasing the analysis of the scattering spectrum, through which the chip’s dislocation density, carrier concentration, and etching damage can be obtained.
• A system combining a high-pixel digital camera and microscope can detect defective chips by precisely measuring the brightness of individual chips.

MicroLED Patent Analysis: A Quick Overview 

As per the MicroLED industry IP landscape report from Yole Development, the number of MicroLED patents is now over 8,900, filed by almost 480 organizations. 

• While leaders such as Apple/Luxvue, XCeleprint, Sony, and others have been active in microLED patents, Chinese companies and other display makers have significantly surged since 2018. 
• Among panel makers, BOE strongly dominated IP activity in 2019, followed by LG, AUO, Samsung, CSOT, Tianma, Innolux, CEC Panda, and OLED specialist Visionox. BOE now ranks first with almost double the amount of patent families (195 granted + pending) compared to LG, which ranks second.
• Apple, however, still leads regarding granted patents and the total amount of citations accumulated by its portfolio.
• Apple invested over $3 billion in microLED R&D. However, In early 2024, Apple decided to cancel its microLED smartwatch display project, and its current microLED plans are unknown.

Sum It Up

The trends in microLED patent analysis reveal a notable overall level of creativity and diversity of approaches deployed to address microLED display technology roadblocks. 

However, established players should not underestimate the potential of Chinese competitors regarding the patent portfolio’s inconsistent value. From a technology standpoint, more than 20 companies have now publicly demonstrated microLED display prototypes. 

However, more effort is needed to reach the quality and manufacturability required for consumer displays. The mass transfer and chip efficiency problems could be resolved as confidence increases.

While microLED technology is advancing rapidly, significant manufacturing and technical challenges remain before widespread consumer display production.